Laser radar device for seawater multi-parameter detection
By adopting the design of coaxial and range-axis dual-received field of view channels in the marine lidar device, the problem of single measurement parameters and signal interaction in the prior art is solved, and a multi-parameter measurement and a simple structure lidar device is realized, which is suitable for multi-parameter detection of seawater.
Patent Information
- Application Number
- CN202421410918.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-20
- Publication Date
- 2025-06-17
- Estimated Expiration
- 2034-06-20
AI Technical Summary
Due to structural problems, the existing marine lidar devices have relatively single measurement parameters, and there are problems such as complex structure of the receiving optical path, mutual influence of signals, and loss of received signals due to frequent light spectroscopy during the detection process.
A lidar device for multi-parameter detection of seawater is designed, and adopts a structure of coaxial and range-axis dual-received field of view channels to receive parallel and vertical polarization signals through coaxial field of view channels. The range-axis receiving field of view channels are divided into first and second receiving channels, which are used to receive chlorophyll fluorescent signals and Raman signals of water bodies, respectively.
Multi-parameter measurement is realized, the optical path structure is simple, the signal crosstalk is small, and it can detect 532nm parallel and vertical polarization signals, water Raman signals and chlorophyll fluorescent signals at the same time, avoiding the problems of mutual influence of signals and loss of received signals. It has a simple structure, small size, light weight, and low power consumption. It is suitable for shore, ship-based and airborne platforms.
Smart Images
Figure CN222994680U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of marine optical radar, and particularly relates to a lidar device for multi-parameter detection of seawater. Background Technique
[0002] The ocean area accounts for about 71% of the earth's surface area. It is an important strategic space for the development of the world economy and society, and also an important field for studying climate change and earth science. Its role and status in the global economic and social development and marine ecological environment protection are becoming increasingly prominent.
[0003] The marine ecological environment is mainly composed of seawater, marine organisms, suspended substances, and organic and inorganic substances dissolved in seawater. The main parameters characterizing the marine environment are marine phytoplankton chlorophyll, suspended substances, colored dissolved organic matter (CDOM), and seawater optical parameters such as seawater attenuation coefficient and absorption coefficient. The research on marine environmental parameters is of great significance to many fields such as marine biochemistry, physical oceanography, marine fishery, and global climate change.
[0004] Marine exploration lidar is an active optical remote sensing detection technology. By emitting laser into seawater and receiving the echo signals generated after the laser acts on targets at different distances, the vertical profile information of seawater surface environmental parameters is retrieved. It has the advantages of high spatio-temporal resolution and all-weather detection, and can be carried on various observation platforms such as airplanes and ships. It is an efficient and practical marine environmental parameter detection technology. However, most of the existing marine lidars have relatively single measurement parameters due to structural problems, and there are problems such as complex receiving optical path structure, signal interaction, and signal loss caused by frequent beam splitting during the detection process. Therefore, in the data acquisition process before data calculation, how to obtain signals without missing and signal interaction is an urgent problem for those skilled in the art. Summary of the Invention
[0005] Aiming at the problems existing in the prior art, the purpose of the utility model is to provide a lidar device for multi-parameter detection of seawater, which has multi-parameter measurement, a simple optical path structure, and small signal crosstalk.
[0006] To achieve the above object, the technical solution adopted by the present utility model is as follows: A lidar device for seawater multi-parameter detection, comprising a laser emission component, a signal reception component, and a data acquisition and signal processing component. The signal reception component includes a coaxial reception field-of-view channel and a paraxial reception field-of-view channel. The laser emission component emits a laser beam, and the backscattered optical signal generated by the interaction of the laser beam with the water medium is received by the signal reception component and converted into an electrical signal. The data acquisition and signal processing component acquires the electrical signal and performs data processing on the electrical signal. The reception optical axis of the coaxial reception field-of-view channel coincides with the emission optical axis of the laser beam, and the reception optical axis of the paraxial reception field-of-view channel is parallel to the emission optical axis of the laser beam.
[0007] For the above lidar device for seawater multi-parameter detection, the coaxial reception field-of-view channel is used to receive the parallel and perpendicular polarization components of the echo signal, and includes a coaxial mounting plate and coaxial optical elements. The coaxial optical elements are sequentially arranged on the coaxial mounting plate. The coaxial optical elements include a coaxial telescope, a coaxial variable aperture diaphragm, a coaxial collimating lens, a coaxial narrowband interference filter, a coaxial polarization beam splitting cube, a coaxial parallel polarization channel converging lens, a coaxial vertical polarization channel converging lens, a coaxial parallel polarization channel photodetector, and a coaxial vertical polarization channel photodetector. The coaxial parallel polarization channel photodetector and the coaxial vertical polarization channel photodetector convert the backscattered optical signal into the electrical signal and transmit the electrical signal to the data acquisition and signal processing component for acquisition and processing.
[0008] For the above lidar device for seawater multi-parameter detection, the paraxial reception field-of-view channel includes a paraxial mounting plate and paraxial optical elements. The paraxial optical elements include a paraxial telescope, a paraxial variable aperture diaphragm, a paraxial collimating lens, and a dichroic mirror. The paraxial reception field-of-view channel is divided into a first reception channel and a second reception channel by the dichroic mirror. The first reception channel is used to receive the chlorophyll fluorescence signal, and the second reception channel is used to receive the Raman signal of the water body. The first reception channel includes a paraxial first reception channel narrowband interference filter, a paraxial first reception channel converging lens, and a paraxial first reception channel photodetector. The second reception channel includes a paraxial second reception channel narrowband interference filter, a paraxial second reception channel converging lens, and a paraxial second reception channel photodetector. The paraxial optical elements are sequentially arranged on the paraxial mounting plate. The paraxial first reception channel photodetector and the paraxial second reception channel photodetector convert the backscattered optical signal into the electrical signal and transmit the electrical signal to the data acquisition and signal processing component for acquisition and processing.
[0009] The above lidar device for multi-parameter detection of seawater, wherein the laser emission component includes a pulsed laser, a half-wave plate, a first reflector, and a second reflector. The pulsed laser emits a laser beam, the polarization direction of the laser beam is adjusted by the half-wave plate, and the laser is emitted into the water body through the first reflector and the second reflector. The second reflector is fixedly installed at the center position of the receiving mirror surface of the coaxial telescope.
[0010] For the above lidar device for multi-parameter detection of seawater, the pulsed laser is a laser with a wavelength of 532 nm and a pulse width less than 5 ns.
[0011] For the above lidar device for multi-parameter detection of seawater, the data acquisition and signal processing component includes a data acquisition card and an industrial control computer. The data acquisition card has no less than four detection channels, and the detection channels are respectively connected to the coaxial parallel polarization channel photodetector, the coaxial vertical polarization channel photodetector, the off-axis first receiving channel photodetector, and the off-axis second receiving channel photodetector through cable lines. The data acquisition card is integrated in the industrial control computer.
[0012] For the lidar device for multi-parameter detection of seawater according to any one of the above, the lidar device further includes a housing and a pan-tilt. The laser emission component, the signal receiving component, and the data acquisition and signal processing component are arranged in the housing. An emission hole for the laser beam is provided on the housing. The pan-tilt is arranged outside the housing and is connected to a fixed object. The pan-tilt adjusts the angle between the emission hole and the water quality plane.
[0013] The beneficial effects of the lidar device for multi-parameter detection of seawater of the present utility model are as follows: By setting coaxial and off-axis dual receiving field-of-view channels, 532 nm parallel and vertical polarization signals, water Raman signals, and chlorophyll fluorescence signals can be detected simultaneously. Compared with a single field of view, problems such as complex receiving optical path structure, signal interaction, and receiving signal loss caused by frequent beam splitting are prevented. It has a simple structure, small size, light weight, low power consumption, is convenient for mobile carrying, and has a high degree of automation, can be remotely controlled, and can be used on experimental platforms such as the shore, shipborne, and airborne to conduct long-term unattended observations of marine environmental parameters. By setting a half-wave plate, the polarization direction of the laser can be adjusted. By setting a pan-tilt, the angle at which the laser beam enters the water quality can be controlled. By using coaxial and off-axis variable-aperture diaphragms, stray light can be filtered out and the size of the field of view angle can be changed at the same time. By setting polarization channels, parallel and vertical polarization signals can be collected separately. By setting a dichroic mirror, the laser beam is divided into two beams of light for separate acquisition and processing, so that the chlorophyll concentration of seawater can be obtained through data processing and parameter inversion. Description of the Drawings
[0014] Figure 1Schematic diagram of the overall structure of an embodiment of the marine exploration lidar system proposed by the present utility model;
[0015] Figure 2 Schematic diagram of the optical path structure of the marine exploration lidar system in an embodiment of the present utility model;
[0016] Figure 3 Schematic diagram of data processing of the marine exploration lidar system in an embodiment of the present utility model. Detailed implementation manners
[0017] To enable those skilled in the art to better understand the technical solutions of the present utility model, the present utility model will be described below in conjunction with the detailed implementation manners and the accompanying drawings.
[0018] Embodiment 1
[0019] As Figures 1-3 shown, a lidar device for seawater multi-parameter detection is used for data acquisition during seawater multi-parameter detection, and the calculation can be completed by an existing single calculation method. As Figure 1 shown, the multi-parameter lidar device mainly includes: a laser emission component 1, a signal reception component 2, and a data acquisition and signal processing component 3. The laser emission component 1 is used to generate a laser beam, the signal reception component 2 is used to receive the lidar echo signals in different fields of view and convert them into electrical signals, and the data acquisition and signal processing component 3 is used to perform data acquisition and processing on the electrical signals generated in the signal reception component 2. The laser emission component 1, the signal reception component 2, and the data acquisition and signal processing component 3 are jointly installed in a housing, and a transmission hole for the laser beam and the echo signal to enter and exit is opened on the housing.
[0020] Considering the requirements of system scanning detection, adjust the emission angle of the emitted laser, and install the dual-field-of-view marine exploration lidar on a pan-tilt 4. When observing on the shore or a shipborne platform, the angle of the laser incident on the target water body can be electrically controlled through the pan-tilt. The pan-tilt is fixedly connected to the shore or the shipborne platform. According to actual requirements, the pan-tilt and the housing can be rotatably connected or fixedly connected. When rotatably connected, a protrusion-ear plate structure can be used, with the protrusion provided at the top of the pan-tilt and the ear plate provided below the housing, and the two are connected by bolts and shaft holes. Similarly, other existing rotatable connection methods can also be used to connect the pan-tilt and the housing.
[0021] As Figure 2 shown, the laser emission component 1 includes a pulsed laser 1-1, a half-wave plate 1-2, a first reflector 1-3, and a second reflector 1-4. The pulsed laser 1-1 emits pulsed laser, adjusts the polarization direction of the laser through the half-wave plate 1-2, and finally emits the laser into the water body through the first reflector 1-3 and the second reflector 1-4.
[0022] To improve the underwater distance resolution of lidar detection, the pulsed laser 1-1 is preferably a laser with a wavelength of 532 nm and a pulse width of less than 5 ns.
[0023] The signal receiving component 2 adopts a dual-field-of-view structure, including a coaxial receiving field-of-view channel and a paraxial receiving field-of-view channel. When the lidar device is operating normally, the receiving optical axis of the coaxial receiving field-of-view channel and the transmitting optical axis of the laser beam completely coincide, and the receiving optical axis of the paraxial receiving field-of-view channel and the transmitting optical axis of the laser beam are in a parallel state.
[0024] The coaxial receiving field-of-view channel is mainly used to receive polarized signals parallel and perpendicular to the laser beam emitted by the 532-nm laser. It includes a coaxial receiving telescope 2-1, a coaxial variable aperture diaphragm 2-2, a coaxial collimating lens 2-3, a coaxial narrowband interference filter 2-4, a coaxial polarization beam splitting cube 2-5, a coaxial parallel polarization channel converging lens 2-6, a coaxial parallel polarization channel photodetector 2-7, a coaxial vertical polarization channel converging lens 2-8, and a coaxial vertical polarization channel photodetector 2-9. The second reflector 1-4 is fixedly installed at the center position of the receiving mirror surface of the coaxial receiving telescope 2-1. By controlling the emission direction of the laser beam, the transmitting optical axis coincides with the receiving optical axis of the receiving field of view.
[0025] The paraxial receiving field-of-view channel is divided into a first receiving channel and a second receiving channel by a dichroic mirror 2-13. The first receiving channel is used to receive chlorophyll fluorescence signals, and the second receiving channel is used to receive Raman signals of the water body. The paraxial receiving field-of-view channel includes a paraxial receiving telescope 2-10, a paraxial variable aperture diaphragm 2-11, a paraxial collimating lens 2-12, a dichroic mirror 2-13, a paraxial first receiving channel narrowband interference filter 2-14, a paraxial first receiving channel converging lens 2-15, a paraxial first receiving channel photodetector 2-16, a paraxial second receiving channel narrowband interference filter 2-17, a paraxial second receiving channel converging lens 2-18, and a paraxial second receiving channel photodetector 2-19. By adjusting the paraxial receiving telescope 2-10, the receiving optical axis of the paraxial receiving field of view and the transmitting optical axis of the laser beam are made parallel.
[0026] The data acquisition and signal processing component 3 includes a data acquisition card 3-1 and an industrial control computer 3-2. The data acquisition card 3-1 has no less than 4 detection channels and is connected to four photodetectors, namely the coaxial parallel polarization channel photodetector, the coaxial vertical polarization channel photodetector, the paraxial first receiving channel photodetector, and the paraxial second receiving channel photodetector in the signal receiving component 2 through coaxial cable lines. The data acquisition card is integrated in the industrial control computer 3-2 and can store the acquired signals in the industrial control computer 3-2 to realize data display and processing.
[0027] In the process of obtaining data by the device described in this embodiment, after obtaining the data, it can be used for subsequent data calculations.
[0028] Embodiment 2
[0029] This embodiment mainly describes the calculation of the data obtained in Embodiment 1. After obtaining data by a lidar device for multi-parameter detection of seawater described above, during its use, the data processing process of the multi-parameter lidar device for ocean detection mainly includes raw data 5, standardized data 6, attenuation coefficient 7, suspended sediment concentration 8, and chlorophyll concentration 9. The raw data 5 is preprocessed to obtain the standardized data 6. The preprocessing mainly removes interference signals, filters background noise, performs profile correction, and time-domain averaging on the raw data 5 to obtain a smooth echo signal. The attenuation coefficient 7 can be obtained by solving and inverting from the standardized data 6 through the marine lidar equation (1):
[0030]
[0031] where P(z) is the echo power received by the lidar, P0 is the average power of the emitted laser pulse, T a is the one-way transmittance of the atmosphere, T s is the one-way transmittance of the water surface, η is the system efficiency, O(z) is the overlap factor of the lidar system, c is the speed of light in a vacuum, τ is the laser pulse width, n is the refractive index of the water body, A is the receiving area of the telescope, H is the working height of the lidar, z is the depth of the seawater being detected, β π and α are the 180° volume scattering function and the lidar attenuation coefficient of the water body, respectively.
[0032] Under the conditions of the marine lidar equation (1) described above, the measurement principle of the chlorophyll concentration 9 is as follows:
[0033] Chlorophyll a in the water body will generate chlorophyll a fluorescence signal under laser induction. The concentration of chlorophyll a in seawater and the intensity of the chlorophyll a fluorescence signal can be approximately considered to be linearly related. Therefore, the chlorophyll a concentration information can be obtained from the intensity of the detected chlorophyll a fluorescence signal. Under the consideration of the quasi-single scattering approximation, the intensity of the chlorophyll a fluorescence signal received by the lidar system satisfies the lidar equation and can be described as Equation (2):
[0034]
[0035] where, P F (z) is the intensity of the chlorophyll a fluorescence signal received by the system, K1 is the system constant of the chlorophyll a fluorescence channel, n F , σ F are the chlorophyll a concentration and the chlorophyll a fluorescence scattering cross-section, respectively, kL is the seawater diffuse attenuation coefficient of the laser wavelength, k F is the seawater diffuse attenuation coefficient of the fluorescence scattering wavelength of chlorophyll a.
[0036] In the process of retrieving the chlorophyll a concentration from the chlorophyll a fluorescence intensity signal obtained by Equation (2), it is necessary to normalize and calibrate the chlorophyll a fluorescence signal using the seawater Raman scattering signal. The intensity of the seawater Raman scattering signal satisfies the lidar equation and can be described by Equation (3):
[0037]
[0038] where, P R (z) is the intensity of the Raman scattering signal received by the system, K2 is the system constant of the Raman channel, n R , σ R are the Raman scattering concentration and the Raman scattering cross section respectively, and k R is the seawater diffuse attenuation coefficient of the Raman scattering wavelength.
[0039] The uncertain factors of the receiving and transmitting systems and parameters such as the seawater diffuse attenuation coefficient that affect the echo power are eliminated by the ratio of Equation (2) and Equation (3), and are described by Equation (4):
[0040]
[0041] where, n F (z) is the chlorophyll a concentration value at the detection depth of z, C1 is a constant obtained by experimental fitting, and finally the chlorophyll concentration information in seawater is obtained through calibration and inversion.
[0042] Under the conditions of the marine lidar Equation (1) described above, the measurement principle of the suspended sediment concentration 8 is as follows:
[0043] Since Mie scattering is mainly caused by the suspended sediment in seawater, the intensity of the Mie scattering signal shows a linear correlation with the suspended sediment concentration. Therefore, as long as the intensity of the Mie scattering signal is measured, the suspended sediment concentration information in seawater can be obtained. Considering the quasi-single scattering situation, the intensity of the Mie scattering signal received by the lidar system satisfies the lidar equation and can be described by Equation (5):
[0044]
[0045] where, P M (z) is the intensity of the Mie scattering signal received by the system, K3 is the system constant of the Mie scattering channel, n M , σ M are the concentration and cross section factor of the suspended sediment in seawater.
[0046] In the process of inverting the concentration of suspended sediment using the Mie scattering signal intensity obtained by Equation (5), it is necessary to calibrate the Mie scattering signal using the seawater Raman scattering signal normalization technique. The uncertain factors of the receiving and transmitting systems that affect the echo power and parameters such as the seawater diffuse attenuation coefficient are eliminated by the ratio of Equation (3) and Equation (5), which is described as Equation (6):
[0047]
[0048] Among them, n M (z) is the concentration value of suspended sediment at a detection depth of z. C2 is a constant obtained by experimental fitting. Finally, the concentration information of suspended sediment in seawater is obtained through calibration inversion.
[0049] The calculation of the above data depends on the data acquisition process of a lidar device for seawater multi-parameter detection provided by this technical solution. During the calculation process, in addition to using the calculation method provided by this technical solution, the calculation method for single-parameter measurement in the prior art can also be used. And this device is mainly used for calculating real-time signal acquisition. Based on the data obtained by using this device, the detection of water body polarization signal, water body Raman signal, and chlorophyll fluorescence signal can be carried out, and information such as seawater optical parameters, suspended sediment concentration, and chlorophyll concentration can be inversely obtained. Specifically, the specific working process of this utility model is as follows:
[0050] The pulsed laser 1-1 emits pulsed laser at 532 nm. The polarization direction of the laser is adjusted by the half-wave plate 1-2, and finally the laser is emitted into the water body through the first reflector 1-3 and the second reflector 1-4. The angle of laser incidence into the seawater is controlled by the pan-tilt.
[0051] The coaxial receiving field-of-view channel acquires the echo signal. The echo signal is first received by the coaxial receiving telescope 2-1, and the stray light is filtered by the coaxial variable small aperture diaphragm 2-2 at the intersection point. The coaxial variable small aperture diaphragm also plays a role in changing the field-of-view angle. Then the signal passes through the coaxial collimating lens 2-3 and is filtered by the coaxial narrowband interference filter 2-4. A polarization channel is set in the subsequent optical path for separately collecting the 532 nm parallel and perpendicular polarization signals. After the coaxial polarization beam-splitting cube 2-5 divides the optical signal into two polarized lights of 532 nm parallel and 532 nm perpendicular, they are respectively converged to the coaxial parallel polarization channel photodetector 2-7 and the coaxial vertical polarization channel photodetector 2-9 through the coaxial parallel polarization channel converging lens 2-6 and the coaxial vertical polarization channel converging lens 2-8. After the optical signal is converted into an electrical signal, it is collected and processed by the data acquisition card 3-1 and the industrial control computer 3-2, so as to obtain the attenuation coefficient 7 and the suspended sediment concentration 8 of seawater through data processing and parameter inversion.
[0052] The echo signal is obtained through the paraxial receiving field-of-view channel. The echo signal is first received by the paraxial receiving telescope 2-10. The paraxial variable small-aperture diaphragm 2-11 at the focal point is used to change the field-of-view angle. Then it is collimated by the paraxial collimating lens 2-12 and is split into a first receiving channel and a second receiving channel by the dichroic mirror 2-13. The stray light is filtered out by the paraxial first receiving channel narrowband interference filter 2-14 and the paraxial second receiving channel narrowband interference filter 2-17 respectively. Then they are converged by the paraxial first receiving channel converging lens 2-15 and the paraxial second receiving channel converging lens 2-18 respectively, and the optical signals are converted into electrical signals by the paraxial first receiving channel photodetector 2-16 and the paraxial second receiving channel photodetector 2-19 respectively. The data acquisition card 3-1 and the industrial control computer 3-2 are used for acquisition and processing, so as to obtain the chlorophyll concentration 9 of seawater through data processing and parameter inversion.
[0053] The above embodiments are only for explaining the structural concept and characteristics of the present invention, and the purpose is to enable those ordinary technicians in the art to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the essence of the content of the present invention should be covered within the protection scope of the present invention.
Claims
1. A laser radar device for seawater multi-parameter detection, comprising a laser emission component, a signal receiving component, a data acquisition and signal processing component, characterized in that: The signal receiving component includes a coaxial receiving field channel and a paraxial receiving field channel, the laser emitting component emits a laser beam, and the echo light signal of the interaction between the laser beam and the water medium is received by the signal receiving component and converted into an electrical signal, and the data acquisition and signal processing component acquires the electrical signal and performs data processing on the electrical signal; The receiving optical axis of the coaxial receiving field channel coincides with the emitting optical axis of the laser beam, and the receiving optical axis of the paraxial receiving field channel is parallel to the emitting optical axis of the laser beam.
2. The laser radar device for seawater multi-parameter detection according to claim 1, characterized in that: The coaxial receiving field of view channel is used to receive polarization components parallel and perpendicular to the echo signal, and includes a coaxial mounting plate and a coaxial optical element. The coaxial optical element is sequentially arranged on the coaxial mounting plate. The coaxial optical element includes a coaxial telescope, a coaxial variable aperture diaphragm, a coaxial collimating lens, a coaxial narrow-band interference filter, a coaxial polarization beam splitting cube, a coaxial parallel polarization channel converging lens, a coaxial vertical polarization channel converging lens, a coaxial parallel polarization channel photoelectric detector, and a coaxial vertical polarization channel photoelectric detector. The coaxial parallel polarization channel photoelectric detector and the coaxial vertical polarization channel photoelectric detector convert the echo light signal into the electrical signal, and transmit the electrical signal to the data acquisition and signal processing component for acquisition and processing.
3. The laser radar device for seawater multi-parameter detection according to claim 2 is characterized in that: The paraxial receiving field channel includes a paraxial mounting plate and a paraxial optical element. The paraxial optical element includes a paraxial telescope, a paraxial variable aperture diaphragm, a paraxial collimating lens, and a dichroic mirror. The paraxial receiving field channel is divided into a first receiving channel and a second receiving channel by the dichroic mirror. The first receiving channel is used to receive chlorophyll fluorescence signals, and the second receiving channel is used to receive Raman signals of water bodies. The first receiving channel includes a paraxial first receiving channel narrow-band interference filter, a paraxial first receiving channel converging lens, and a paraxial first receiving channel photoelectric detector. The second receiving channel includes a paraxial second receiving channel narrow-band interference filter, a paraxial second receiving channel converging lens, and a paraxial second receiving channel photoelectric detector. The paraxial optical elements are sequentially arranged on the paraxial mounting plate. The paraxial first receiving channel photoelectric detector and the paraxial second receiving channel photoelectric detector convert the echo light signal into the electrical signal, and transmit the electrical signal to the data acquisition and signal processing component for acquisition and processing.
4. The laser radar device for seawater multi-parameter detection according to claim 3 is characterized in that: The laser emitting assembly includes a pulse laser, a half-wave plate, a first reflector, and a second reflector. The pulse laser emits a laser beam, and the polarization direction of the laser beam is adjusted by the half-wave plate. The laser beam is emitted into the water body through the first reflector and the second reflector. The second reflector is fixedly installed at the center position of the receiving mirror of the coaxial telescope.
5. The laser radar device for seawater multi-parameter detection according to claim 4 is characterized in that: The pulse laser is a laser with a wavelength of 532nm and a pulse width of less than 5ns.
6. The laser radar device for seawater multi-parameter detection according to claim 5, characterized in that: The data acquisition and signal processing components include a data acquisition card and an industrial computer. The data acquisition card uses no less than four detection channels, and the detection channels are respectively connected to the coaxial parallel polarization channel photoelectric detector, the coaxial vertical polarization channel photoelectric detector, the paraxial first receiving channel photoelectric detector, and the paraxial second receiving channel photoelectric detector through cables. The data acquisition card is integrated in the industrial computer.
7. The laser radar device for seawater multi-parameter detection according to any one of claims 1 to 6, characterized in that: The laser radar device also includes a shell and a gimbal. The laser emitting component, signal receiving component, data acquisition and signal processing component are arranged in the shell. The shell is provided with an emitting hole for the laser beam. The gimbal is arranged on the outside of the shell and connected to a fixed object. The gimbal adjusts the angle between the emitting hole and the water quality plane.